Who is a libertarian?

Zero Aggression Principle ("Zap")

"Zero Aggression
Principle":

A libertarian is a person who believes that no one has
the right, under any circumstances, to initiate force against
another human being for any reason whatever; nor will a
libertarian advocate the initiation of force, or delegate it to
anyone else.

Those who act consistently with this principle are
libertarians, whether they realize it or not. Those who fail
to act consistently with it are not libertarians, regardless
of what they may claim.
 L. Neil Smith